CVE-2026-74221

HIGHPre-NVD 8.28.2—
EchelonGraph scoreHIGH confidence

Score 8.2 from GitHub Security Advisory (severity: HIGH) published 2026-09-30. A secondary CVSS source baseline 8.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this week
8.2EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 8.2Exploit: None knownExposed services: Not assessed

An upstream fix is merged but not yet released — mitigate (WAF / firewall / segmentation) until the release ships, then apply it.

U-Boot before 2026.10-rc5 contains a buffer overflow in nfs_readlink_reply() function in net/nfs-common.c when processing NFS server responses. A malicious NFS server can send crafted READLINK replies with negative or oversized symlink length values to corrupt memory and crash the bootloader.

CVSS v3
8.2
EG Score
8.2HIGHhigh confidence
EG Risk
52
EG Risk 52/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity82% × 45%
Exploitation0% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high until it ships, then apply the release.
EPSS PROB
0.3%
EPSS %ILE
25th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high until it ships, then apply the release.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 29, 2026

Last Modified

September 30, 2026

Advisory Details (4)

Auto-updated Sep 29, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit.
generic

U-Boot before 2026.10-rc5 Buffer Overflow via NFS READLINK | Advisories | VulnCheck

https://www.vulncheck.com/advisories/u-boot-before-2026.10-rc5-buffer-overflow-via-nfs-readlink
generic

GitHub - u-boot/u-boot: "Das U-Boot" Source Tree · GitHub

https://github.com/u-boot/u-boot
generic

u-boot/net/nfs-common.c at v2026.07 · u-boot/u-boot · GitHub

https://github.com/u-boot/u-boot/blob/v2026.07/net/nfs-common.c#L643
github_commit

commit 1c0aff3a5fbf (u-boot/u-boot)

Fix landed in u-boot/u-boot commit 1c0aff3a5fbf — awaiting tagged release

https://github.com/u-boot/u-boot/commit/1c0aff3a5fbfeee7a8948f624e0b8554e6e0d8fd

Vendor Advisories for CVE-2026-74221(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
u-boot2023.01+dfsg-2 ... 2025.01-3.2 (24 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
u-boot2025.01-3, 2025.01-3+deb13u1, 2025.01-3.1, 2025.01-3.2
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
u-boot2025.01-3, 2025.01-3.1, 2025.01-3.2
  • every version on: no fix on record
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 31× in last 7d / 31× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-05 05:14 UTCEG score recompute
  2. 2026-10-05 05:14 UTCVendor advisory
  3. 2026-10-05 05:14 UTCGHSA enrichment
  4. 2026-10-04 23:22 UTCEPSS rescore
  5. 2026-10-04 17:12 UTCVendor advisory
  6. 2026-10-04 17:11 UTCGHSA enrichment
  7. 2026-10-04 05:09 UTCVendor advisory
  8. 2026-10-04 05:09 UTCGHSA enrichment
  9. 2026-10-03 17:07 UTCEG score recompute
  10. 2026-10-03 17:07 UTCVendor advisory
  11. 2026-10-03 17:06 UTCGHSA enrichment
  12. 2026-10-03 14:26 UTCEPSS rescore
  13. 2026-10-03 05:04 UTCEG score recompute
  14. 2026-10-03 05:04 UTCGHSA enrichment
  15. 2026-10-02 17:02 UTCGHSA enrichment
  16. 2026-10-02 05:00 UTCEG score recompute
  17. 2026-10-02 05:00 UTCGHSA enrichment
  18. 2026-10-01 19:50 UTCEPSS rescore
  19. 2026-10-01 16:57 UTCGHSA enrichment
  20. 2026-10-01 04:51 UTCGHSA enrichment
  21. 2026-09-30 16:45 UTCEG score recompute
  22. 2026-09-30 16:45 UTCGHSA enrichment
  23. 2026-09-30 14:30 UTCEG score recompute
  24. 2026-09-30 14:30 UTCGHSA enrichment
  25. 2026-09-30 13:53 UTCEG score recompute
Show 6 more
  1. 2026-09-30 13:52 UTCGHSA enrichment
  2. 2026-09-30 10:33 UTCEG score recompute
  3. 2026-09-30 10:32 UTCGHSA enrichment
  4. 2026-09-29 22:25 UTCEG score recompute
  5. 2026-09-29 21:37 UTCEG score recompute
  6. 2026-09-29 21:33 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-74221?
CVE-2026-74221 is a high vulnerability published on September 29, 2026. U-Boot before 2026.10-rc5 contains a buffer overflow in nfsreadlinkreply() function in net/nfs-common.c when processing NFS server responses. A malicious NFS server can send crafted READLINK replies with negative or oversized symlink length values to corrupt memory and crash the bootloader.
When was CVE-2026-74221 disclosed?
CVE-2026-74221 was first published on September 29, 2026, with the most recent update on September 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-74221 actively exploited?
CVE-2026-74221 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (25th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-74221?
CVE-2026-74221 has a CVSS base score of 8.2 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-74221?
An upstream fix for CVE-2026-74221 has been merged but is not yet in a tagged release. Until it ships, restrict network exposure of the affected system or apply the vendor's mitigation, then update to the release that contains the fix. The vendor advisories EchelonGraph has for CVE-2026-74221 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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